Wick applicators are often used to apply herbicides to weeds or other undesirable vegetation that typically grow among crops. Typically, a wick applicator includes an elongated tube that has an internal chamber for holding the herbicide. A series of dispensing holes are provided in the elongated tube and a wicking material or fabric is usually wrapped around the elongated tube adjacent the dispensing openings. It is known to provide a main on/off valve that is communicatively open to the internal chamber of the wick applicator. By opening the on/off valve, the wicking material wrapped around the elongated tube will, through a wicking action, draw the herbicide from the wick applicator. Once the wicking material has become wet with the herbicide, then the wick applicator can be used to directly engage and directly apply the herbicide to weeds and other undesirable vegetation. For a more complete understanding and appreciation of conventional wick applicators, reference is made to U.S. Pat. No. 4,884,362, the disclosure thereof being expressly incorporated herein by reference.
One of the major problems and drawbacks with all wick applicators is the inability to calibrate them and control the flow of liquid from the internal holding chamber to the outer wicking material. Experience with wick applicators reveals two extreme situations. First, there is the case where the flow rate of chemical is so low that the field operation is totally ineffective or is at best, marginally effective. Obviously, if an insufficient amount of the chemical is reaching the targeted foliage, then clearly the field operation is not satisfactory. Equally a problem is the situation where one finds the wicking material to be overly saturated. It is not uncommon to find operations where the wicking material is so saturated that the chemical is actually dripping from the wicking material. Not only is the wasteful but this problem can and will lead to serious crop damage. Moreover, the waste is even accelerated by the evaporative effects caused by the wick applicator being moved through the field at an appreciable rate.
Therefore, there has been and there continues to be a need for a wick applicator that includes some reliable means to calibrate the wick applicator and to in the end control the application rate of the applicator.
Turning briefly to a discussion of cotton and the application of growth regulating chemicals to cotton plants and their foliage, it is appreciated that it has for some time been standard practice in cotton farming to treat the growing cotton plants with a growth regulating chemical. To date, it appears that this operation is generally carried out by a conventional spraying procedure.
Before discussing the shortcomings of spraying a growth regulating chemical on cotton, it might be beneficial to basically review some of the reasons for applying such a chemical to cotton. Generally, plant growth regulators modify cotton plants in a number of beneficial ways. Applying growth regulators to cotton plants allow the cotton grower to manage the cotton crop for short season production and reduces the risk of poor quality and yield due to the harvest season being delayed or prolonged for reasons not controlled by the cotton grower. The application of growth regulators to cotton will reduce the height of certain cotton plants and will provide a more open canopy. At the same time, boll retention will be improved and in fact, the plant will grow larger bolls with less boll rot and improved defoliation. In the end, this will reduce trash in the cotton crop and will lower ginning costs. Therefore, it can be said that the cultural practice of applying growth regulators to cotton is well-known and is an accepted practice throughout the United States and indeed the world.
As pointed out above, plant growth regulators are generally applied to cotton by spraying. Sprayers used for this cultural practice are most often multi-row sprayers that take the form of a self-propelled overhead sprayer or a sprayer of the type that is mounted on a farm tractor. There are a number of serious problems with spraying cotton with a growth regulator. The most visible drawback and problem concerns how the operator chooses which plants to spray and which plants not to spray. It is an unusual occurrence, especially with respect to a first field operation, where all of the plants are the same size and the cotton grower desires to apply the plant growth regulator uniformly across a field. The typical situation is where a certain percentage of the cotton plants are taller than others and it is the desire and intent of the grower to only apply the growth regulating composition to these random occurring taller plants. Thus, it is customary to find the operator traveling through the field and periodically cutting the sprayer on and off. Obviously, this is a very imprecise way of applying the growth regulating composition to the intended plants. It is at best guess work, and it is especially so in view of the fact that the spraying system usually covers a large number of rows and a relatively large area in a small time sequence. Thus, the operator can only hope to minimize the inefficiencies and make the best of a bad situation.
Therefore, there has and continues to be a need for an effective way of applying a growth regulating chemical or composition directly to targeted cotton plants.